CAS registry number

Information about CAS registry number

CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. They are also referred to as CAS numbers, CAS RNs or CAS #s.

Chemical Abstracts Service (CAS), a division of the American Chemical Society, assigns these identifiers to every chemical that has been described in the literature. The intention is to make database searches more convenient, as chemicals often have many names. Almost all molecule databases today allow searching by CAS number.

As of June 2007, there were 31,745,275 organic and inorganic substances and 59,039,087 sequences in the CAS registry.[1] Around 50,000 new numbers are added each week.

CAS also maintains and sells a database of these chemicals, known as the CAS registry.

Format

A CAS registry number is separated by hyphens into three parts, the first consisting of up to 6 digits, the second consisting of two digits, and the third consisting of a single digit serving as a check digit. The numbers are assigned in increasing order and do not have any inherent meaning. The checksum is calculated by taking the last digit times 1, the next digit times 2, the next digit times 3 etc., adding all these up and computing the sum modulo 10. For example, the CAS number of water is 7732-18-5: the checksum is calculated as (8×1 + 1×2 + 2×3 + 3×4 + 7×5 + 7×6) = 105; 105 mod 10 = 5.

The Chemical Abstracts Service has announced on its web site that it will add an additional digit to new CAS registry numbers, starting about January 2008.

Isomers, enzymes, and mixtures

Different stereoisomers of a molecule receive different CAS numbers: D-glucose has 50-99-7, L-glucose has 921-60-8, α-D-glucose has 26655-34-5, etc. Occasionally, whole classes of molecules receive a single CAS number: the group of alcohol dehydrogenases has 9031-72-5. An example of a mixture with a CAS number is mustard oil (8007-40-7).

Searches

When using CAS numbers for database searches, it is useful to include the numbers of closely related compounds. For instance, to search for information about cocaine (CAS 50-36-2), one should consider including cocaine hydrochloride (CAS 53-21-4), since that is the most common form of cocaine when used as a drug.

Notes

See also

External links

To find the CAS number of a compound given its name, formula or structure, the following free resources can be used:
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polymer is a substance composed of molecules with large molecular mass composed of repeating structural units, or monomers, connected by covalent chemical bonds. The word is derived from the Greek, πολυ, polu, "many"; and μέρος, meros,
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An alloy is a homogeneous hybrid of two or more elements, at least one of which is a metal, and where the resulting material has metallic properties. The resulting metallic substance usually has different properties (sometimes substantially different) from those of its components.
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Chemical Abstracts Service (CAS) is a division of the American Chemical Society, and produces Chemical Abstracts, and related products. It is located in Columbus, Ohio, USA.
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American Chemical Society

Formation 1876
Headquarters Washington, DC
Location  United States
Membership 160,000
Official languages English
President Katie Hunt
Website [1] The American Chemical Society
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June 2007 is the sixth month of that year. It began on a Friday and 30 days later, ended on a Saturday.

International holidays



  • June 4 - Queen's Official Birthday (New Zealand)
  • June 5 - Constitution Day (Denmark)

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A check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary checksum. It consists of a single digit computed from the other digits in the message.
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Modular arithmetic (sometimes called modulo arithmetic, or clock arithmetic) is a system of arithmetic for integers, where numbers "wrap around" after they reach a certain value — the modulus.
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Water is a common chemical substance that is essential to all known forms of life.[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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Stereoisomers are isomeric molecules whose atomic connectivity is the same but whose atomic arrangement in space is different.

Enantiomers

Main article: enantiomer

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Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. The living cell uses it as a source of energy and metabolic intermediate.
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Alcohol dehydrogenases (EC 1.1.1.1 ) are a group of seven dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones.
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The term mustard oil is used for two different oils that are made from mustard seeds:
  • a fatty vegetable oil resulting from pressing the seeds,
  • an essential oil resulting from grinding the seeds, mixing them with water, and extracting the resulting volatile oil by

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In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base (mostly amines). This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid.
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Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the respective enzyme.
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The terms EC-No and EC# refer to the seven-digit code (sometimes called the EC number) that has been allocated by the Commission of the European Communities for commercially available chemical substances within the European Union.
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The IUPAC International Chemical Identifier (InChI) is a textual identifier for chemical substances, designed to provide a human-readable standard way to encode molecular information and to facilitate the search for such information in databases and on the web.
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PubChem is a database of chemical molecules. The system is maintained by the National Center for Biotechnology Information (NCBI), a component of the National Library of Medicine, which is part of the United States National Institutes of Health (NIH).
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smiles

File extension: .smi
Type of format: chemical file format

The simplified molecular input line entry specification or SMILES
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UN numbers or UN IDs are four-digit numbers that identify dangerous goods hazardous substances and articles (such as explosives, flammable liquids, toxic substances, etc.) in the framework of international transport. Some hazardous substances have their own UN numbers (e.g.
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A chemical database is a database specifically designed to store chemical information. Most chemical databases store information on stable molecules. Chemical structures are traditionally represented using lines indicating chemical bonds between atoms and drawn on paper (2D
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A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. A chemical formula is also a short way of showing how a chemical reaction occurs.
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The terms EC-No and EC# refer to the seven-digit code (sometimes called the EC number) that has been allocated by the Commission of the European Communities for commercially available chemical substances within the European Union.
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